Air mattress



FIG. 1 is a perspective view of an air mattress showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a front view thereof;

FIG. 7 is a rear view thereof; and,

FIG. 8 is a rear perspective view thereof, showing the air mattress as used in a vehicle.

The broken lines in FIGS. 1-7 represent the portions of the air mattress that form no part of the claimed design. The broken lines in FIG. 8, showing portions of a vehicle, represent the environment in which the design is used. 

CLAIM The ornamental design for an air mattress, as shown and described. 